A large collection of rat cell lines of nerve, glial, smooth muscle, heart muscle, and skeletal muscle origin have been and will continue to be isolated in our laboratory. Many cell lines have been characterized biochemically and electrophysiologically, and, along with cell lines isolated in other laboratories, will be used to study the differentiation, physiology, and interactions of nerve, muscle, and glia. The study of muscle and mesoderm development will also be extended to the in vivo situation. Clonal nerve lines from the rat central nervous system will be used to study the metabolism and pharmacology of GABA, while other cell lines will be used to examine the metabolism and release of catecholamines and acetylcholine. Since secreted material is likely to play a role in gradients and trophic effects between cells during morphogenesis, the secreted proteins and peptides of the nerve, glial, and muscle cell lines will be examined in detail using a newly developed 2-D protein mapping technique. The role of extracellular substrate attached material in cell-cell and cell-substratum adhesion will also be studied.